/*

 * jctrans.c

 *

 * Copyright (C) 1995, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains library routines for transcoding compression,

 * that is, writing raw DCT coefficient arrays to an output JPEG file.

 * The routines in jcapimin.c will also be needed by a transcoder.

 */



#define JPEG_INTERNALS

#include "jinclude.h"

#include "jpeglib.h"





/* Forward declarations */

LOCAL void transencode_master_selection

	JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));

LOCAL void transencode_coef_controller

	JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays));





/*

 * Compression initialization for writing raw-coefficient data.

 * Before calling this, all parameters and a data destination must be set up.

 * Call jpeg_finish_compress() to actually write the data.

 *

 * The number of passed virtual arrays must match cinfo->num_components.

 * Note that the virtual arrays need not be filled or even realized at

 * the time write_coefficients is called; indeed, if the virtual arrays

 * were requested from this compression object's memory manager, they

 * typically will be realized during this routine and filled afterwards.

 */



GLOBAL void

jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)

{

  if (cinfo->global_state != CSTATE_START)

    ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);

  /* Mark all tables to be written */

  jpeg_suppress_tables(cinfo, FALSE);

  /* (Re)initialize error mgr and destination modules */

  (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo);

  (*cinfo->dest->init_destination) (cinfo);

  /* Perform master selection of active modules */

  transencode_master_selection(cinfo, coef_arrays);

  /* Wait for jpeg_finish_compress() call */

  cinfo->next_scanline = 0;	/* so jpeg_write_marker works */

  cinfo->global_state = CSTATE_WRCOEFS;

}





/*

 * Initialize the compression object with default parameters,

 * then copy from the source object all parameters needed for lossless

 * transcoding.  Parameters that can be varied without loss (such as

 * scan script and Huffman optimization) are left in their default states.

 */



GLOBAL void

jpeg_copy_critical_parameters (j_decompress_ptr srcinfo,

			       j_compress_ptr dstinfo)

{

  JQUANT_TBL ** qtblptr;

  jpeg_component_info *incomp, *outcomp;

  JQUANT_TBL *c_quant, *slot_quant;

  int tblno, ci, coefi;



  /* Safety check to ensure start_compress not called yet. */

  if (dstinfo->global_state != CSTATE_START)

    ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state);

  /* Copy fundamental image dimensions */

  dstinfo->image_width = srcinfo->image_width;

  dstinfo->image_height = srcinfo->image_height;

  dstinfo->input_components = srcinfo->num_components;

  dstinfo->in_color_space = srcinfo->jpeg_color_space;

  /* Initialize all parameters to default values */

  jpeg_set_defaults(dstinfo);

  /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB.

   * Fix it to get the right header markers for the image colorspace.

   */

  jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space);

  dstinfo->data_precision = srcinfo->data_precision;

  dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling;

  /* Copy the source's quantization tables. */

  for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {

    if (srcinfo->quant_tbl_ptrs[tblno] != NULL) {

      qtblptr = & dstinfo->quant_tbl_ptrs[tblno];

      if (*qtblptr == NULL)

	*qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo);

      MEMCOPY((*qtblptr)->quantval,

	      srcinfo->quant_tbl_ptrs[tblno]->quantval,

	      SIZEOF((*qtblptr)->quantval));

      (*qtblptr)->sent_table = FALSE;

    }

  }

  /* Copy the source's per-component info.

   * Note we assume jpeg_set_defaults has allocated the dest comp_info array.

   */

  dstinfo->num_components = srcinfo->num_components;

  if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS)

    ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components,

	     MAX_COMPONENTS);

  for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info;

       ci < dstinfo->num_components; ci++, incomp++, outcomp++) {

    outcomp->component_id = incomp->component_id;

    outcomp->h_samp_factor = incomp->h_samp_factor;

    outcomp->v_samp_factor = incomp->v_samp_factor;

    outcomp->quant_tbl_no = incomp->quant_tbl_no;

    /* Make sure saved quantization table for component matches the qtable

     * slot.  If not, the input file re-used this qtable slot.

     * IJG encoder currently cannot duplicate this.

     */

    tblno = outcomp->quant_tbl_no;

    if (tblno < 0 || tblno >= NUM_QUANT_TBLS ||

	srcinfo->quant_tbl_ptrs[tblno] == NULL)

      ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno);

    slot_quant = srcinfo->quant_tbl_ptrs[tblno];

    c_quant = incomp->quant_table;

    if (c_quant != NULL) {

      for (coefi = 0; coefi < DCTSIZE2; coefi++) {

	if (c_quant->quantval[coefi] != slot_quant->quantval[coefi])

	  ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno);

      }

    }

    /* Note: we do not copy the source's Huffman table assignments;

     * instead we rely on jpeg_set_colorspace to have made a suitable choice.

     */

  }

}





/*

 * Master selection of compression modules for transcoding.

 * This substitutes for jcinit.c's initialization of the full compressor.

 */



LOCAL void

transencode_master_selection (j_compress_ptr cinfo,

			      jvirt_barray_ptr * coef_arrays)

{

  /* Although we don't actually use input_components for transcoding,

   * jcmaster.c's initial_setup will complain if input_components is 0.

   */

  cinfo->input_components = 1;

  /* Initialize master control (includes parameter checking/processing) */

  jinit_c_master_control(cinfo, TRUE /* transcode only */);



  /* Entropy encoding: either Huffman or arithmetic coding. */

  if (cinfo->arith_code) {

    ERREXIT(cinfo, JERR_ARITH_NOTIMPL);

  } else {

    if (cinfo->progressive_mode) {

#ifdef C_PROGRESSIVE_SUPPORTED

      jinit_phuff_encoder(cinfo);

#else

      ERREXIT(cinfo, JERR_NOT_COMPILED);

#endif

    } else

      jinit_huff_encoder(cinfo);

  }



  /* We need a special coefficient buffer controller. */

  transencode_coef_controller(cinfo, coef_arrays);



  jinit_marker_writer(cinfo);



  /* We can now tell the memory manager to allocate virtual arrays. */

  (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo);



  /* Write the datastream header (SOI) immediately.

   * Frame and scan headers are postponed till later.

   * This lets application insert special markers after the SOI.

   */

  (*cinfo->marker->write_file_header) (cinfo);

}





/*

 * The rest of this file is a special implementation of the coefficient

 * buffer controller.  This is similar to jccoefct.c, but it handles only

 * output from presupplied virtual arrays.  Furthermore, we generate any

 * dummy padding blocks on-the-fly rather than expecting them to be present

 * in the arrays.

 */



/* Private buffer controller object */



typedef struct {

  struct jpeg_c_coef_controller pub; /* public fields */



  JDIMENSION iMCU_row_num;	/* iMCU row # within image */

  JDIMENSION mcu_ctr;		/* counts MCUs processed in current row */

  int MCU_vert_offset;		/* counts MCU rows within iMCU row */

  int MCU_rows_per_iMCU_row;	/* number of such rows needed */



  /* Virtual block array for each component. */

  jvirt_barray_ptr * whole_image;



  /* Workspace for constructing dummy blocks at right/bottom edges. */

  JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU];

} my_coef_controller;



typedef my_coef_controller * my_coef_ptr;





LOCAL void

start_iMCU_row (j_compress_ptr cinfo)

/* Reset within-iMCU-row counters for a new row */

{

  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;



  /* In an interleaved scan, an MCU row is the same as an iMCU row.

   * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows.

   * But at the bottom of the image, process only what's left.

   */

  if (cinfo->comps_in_scan > 1) {

    coef->MCU_rows_per_iMCU_row = 1;

  } else {

    if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1))

      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor;

    else

      coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height;

  }



  coef->mcu_ctr = 0;

  coef->MCU_vert_offset = 0;

}





/*

 * Initialize for a processing pass.

 */



METHODDEF void

start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode)

{

  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;



  if (pass_mode != JBUF_CRANK_DEST)

    ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);



  coef->iMCU_row_num = 0;

  start_iMCU_row(cinfo);

}





/*

 * Process some data.

 * We process the equivalent of one fully interleaved MCU row ("iMCU" row)

 * per call, ie, v_samp_factor block rows for each component in the scan.

 * The data is obtained from the virtual arrays and fed to the entropy coder.

 * Returns TRUE if the iMCU row is completed, FALSE if suspended.

 *

 * NB: input_buf is ignored; it is likely to be a NULL pointer.

 */



METHODDEF boolean

compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf)

{

  my_coef_ptr coef = (my_coef_ptr) cinfo->coef;

  JDIMENSION MCU_col_num;	/* index of current MCU within row */

  JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1;

  JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1;

  int blkn, ci, xindex, yindex, yoffset, blockcnt;

  JDIMENSION start_col;

  JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN];

  JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU];

  JBLOCKROW buffer_ptr;

  jpeg_component_info *compptr;



  /* Align the virtual buffers for the components used in this scan. */

  for (ci = 0; ci < cinfo->comps_in_scan; ci++) {

    compptr = cinfo->cur_comp_info[ci];

    buffer[ci] = (*cinfo->mem->access_virt_barray)

      ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index],

       coef->iMCU_row_num * compptr->v_samp_factor,

       (JDIMENSION) compptr->v_samp_factor, FALSE);

  }



  /* Loop to process one whole iMCU row */

  for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row;

       yoffset++) {

    for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row;

	 MCU_col_num++) {

      /* Construct list of pointers to DCT blocks belonging to this MCU */

      blkn = 0;			/* index of current DCT block within MCU */

      for (ci = 0; ci < cinfo->comps_in_scan; ci++) {

	compptr = cinfo->cur_comp_info[ci];

	start_col = MCU_col_num * compptr->MCU_width;

	blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width

						: compptr->last_col_width;

	for (yindex = 0; yindex < compptr->MCU_height; yindex++) {

	  if (coef->iMCU_row_num < last_iMCU_row ||

	      yindex+yoffset < compptr->last_row_height) {

	    /* Fill in pointers to real blocks in this row */

	    buffer_ptr = buffer[ci][yindex+yoffset] + start_col;

	    for (xindex = 0; xindex < blockcnt; xindex++)

	      MCU_buffer[blkn++] = buffer_ptr++;

	  } else {

	    /* At bottom of image, need a whole row of dummy blocks */

	    xindex = 0;

	  }

	  /* Fill in any dummy blocks needed in this row.

	   * Dummy blocks are filled in the same way as in jccoefct.c:

	   * all zeroes in the AC entries, DC entries equal to previous

	   * block's DC value.  The init routine has already zeroed the

	   * AC entries, so we need only set the DC entries correctly.

	   */

	  for (; xindex < compptr->MCU_width; xindex++) {

	    MCU_buffer[blkn] = coef->dummy_buffer[blkn];

	    MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0];

	    blkn++;

	  }

	}

      }

      /* Try to write the MCU. */

      if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) {

	/* Suspension forced; update state counters and exit */

	coef->MCU_vert_offset = yoffset;

	coef->mcu_ctr = MCU_col_num;

	return FALSE;

      }

    }

    /* Completed an MCU row, but perhaps not an iMCU row */

    coef->mcu_ctr = 0;

  }

  /* Completed the iMCU row, advance counters for next one */

  coef->iMCU_row_num++;

  start_iMCU_row(cinfo);

  return TRUE;

}





/*

 * Initialize coefficient buffer controller.

 *

 * Each passed coefficient array must be the right size for that

 * coefficient: width_in_blocks wide and height_in_blocks high,

 * with unitheight at least v_samp_factor.

 */



LOCAL void

transencode_coef_controller (j_compress_ptr cinfo,

			     jvirt_barray_ptr * coef_arrays)

{

  my_coef_ptr coef;

  JBLOCKROW buffer;

  int i;



  coef = (my_coef_ptr)

    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

				SIZEOF(my_coef_controller));

  cinfo->coef = (struct jpeg_c_coef_controller *) coef;

  coef->pub.start_pass = start_pass_coef;

  coef->pub.compress_data = compress_output;



  /* Save pointer to virtual arrays */

  coef->whole_image = coef_arrays;



  /* Allocate and pre-zero space for dummy DCT blocks. */

  buffer = (JBLOCKROW)

    (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,

				C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));

  jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK));

  for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) {

    coef->dummy_buffer[i] = buffer + i;

  }

}

